Field of the Invention
The present invention relates to an optical driver apparatus attachable to optical apparatuses such as video cameras, digital cameras and interchangeable lenses.
Description of the Related Art
Optical apparatuses include ones in which a user's manual operation of an operation member such as a manual operation ring provided around a lens barrel causes a lens to move in its optical axis direction in the lens barrel to perform zooming (variation of magnification) or focusing. However, when the zooming or focusing is performed in video image capturing using such optical apparatuses (interchangeable lenses or cameras), it is often convenient for the user to electrically drive the lens using an actuator.
Japanese Patent Laid-Open No. 2007-108373 discloses an optical driver apparatus that is attached (externally connected) to a lens barrel of an interchangeable lens capable of zooming in response to a user's manual operation of a zoom operation ring and that rotationally drives the zoom operation ring using an actuator in response to a user's operation of a zoom switch.
Furthermore, Japanese Patent No. 2773230 discloses an optical driver apparatus provided with a clutch mechanism and allowing selection between manual zooming and actuator-driven zooming in response to switching of the clutch mechanism.
However, if the optical apparatus to which the optical driver apparatus is attached has a locking mechanism for locking (restraining) motion of the operation member, driving the actuator of the optical driver apparatus when the locking mechanism is in a locking state generates an excessive load in the actuator and in a transmission mechanism (gears or the like) for transmitting a driving force from the actuator to the operation member.